Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Quantos first downs os Bills tiveram quando seu oponente teve 6?
 ###Tabelas: CREATE TABLE list_by_the_world_health_organization_2011 (list_by_the_world_health_organization_2011_id AUTO_INCREMENT PRIMARY KEY, Overall rank INT, Country VARCHAR, Overall life expectancy INT, Male life expectancy INT, Male rank INT, Female life expectancy INT, Female rank INT) CREATE TABLE episode_7–1_march_2008 (episode_7–1_march_2008_id AUTO_INCREMENT PRIMARY KEY, Index VARCHAR, Name VARCHAR, Song VARCHAR, Group Song VARCHAR, Score VARCHAR) CREATE TABLE virginia_counties_and_cities_ranked_by_per_capita_income (virginia_counties_and_cities_ranked_by_per_capita_income_id AUTO_INCREMENT PRIMARY KEY, County or City VARCHAR, Per capita income VARCHAR, Median household income VARCHAR, Median family income VARCHAR, Population INT, Number of households INT) CREATE TABLE tank_locomotives (tank_locomotives_id AUTO_INCREMENT PRIMARY KEY, Class VARCHAR, Number(s) VARCHAR, Quantity INT, Year(s) of Manufacture VARCHAR, Type VARCHAR) CREATE TABLE schedule (schedule_id AUTO_INCREMENT PRIMARY KEY, Game INT, Date VARCHAR, Opponent VARCHAR, Result VARCHAR, Bills points INT, Opponents INT, Bills first downs INT, Record VARCHAR)  
SELECT MIN Bills first downs FROM schedule WHERE Opponents = 6